Yeah car analogies suck.

Diesel is blended differently for winter and summer in many countries. See this for instance https://www.crownoil.co.uk/guides/winter-blend-vs-summer-ble...

Around the skiing season, many automotive magazines will remind diesel drivers to buy “winter diesel” or use additives if e.g. driving up to the Alps or similar cold places.

It’s not so black and white :)